French Postal Codes CEDEX
The system is also used outside Europe, in the Overseas Departments and Territories, but it is the first two digits that identify the department or territory. The French postal code system is also used in Monaco as if it were a French department numbered 98. The digits 00 are used for Military addresses. The digits 20 are used for all of Corsica; Corsica used to be one department numbered 20, but today it is split into two departments numbered as 2A and 2B.
There is also a system known as CEDEX, Courrier d'Entreprise a Distribution EXceptionnelle, designed for recipients of large volumes of mail. A postal code is allocated to each large organization or to post office box holders, ending in three unique digits.